Semi-Ellipsoid LED Package for Uniform Backlight Illumination
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Solution Overview
Problem
Conventional backlight modules with fewer LEDs face challenges in achieving uniform brightness due to wider gaps between LEDs, leading to dark lines and light leakage issues, especially as LCDs become thinner and lighter, requiring a new LED with different angular light distributions in horizontal and vertical directions.
Innovation Solution
A light emitting diode (LED) module with a semi-ellipsoid package structure that embeds the LED die, featuring an elliptic bottom surface and an ellipsoidal surface, which directs light to a light guide plate, allowing for broader angular distribution in the horizontal direction to prevent dark lines and a smaller angular distribution in the vertical direction to prevent light leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If fewer LEDs are used to lower cost, then manufacturing cost is reduced, but gaps between LEDs widen causing dark lines and non-uniform brightness
Solution Approach 1:
The patent applies local quality by designing the package structure with different curvature radii in different directions. The first curvature radius (R1) in the first direction and the second curvature radius (R2) in the second direction are different, creating asymmetric light distribution that locally optimizes illumination in gap areas while maintaining overall brightness uniformity across the display panel.
Solution Approach 2:
The patent employs asymmetry through the elliptical or circular arc cross-section of the package structure. The asymmetric curvature design (different R1 and R2 values) creates non-uniform light distribution that specifically targets and illuminates the gap areas between LEDs, compensating for the reduced LED quantity and preventing dark line formation.
2Illumination intensity
If the angular distribution of light field is increased to cover wider gaps, then brightness uniformity is improved, but light leakage occurs from thinner light guide plates
Solution Approach 1:
The patent applies local quality by designing the package structure with different curvature radii in different directions. The first curvature radius (R1) in the first direction and the second curvature radius (R2) in the second direction are different, creating asymmetric light distribution that locally optimizes illumination in gap areas while maintaining overall brightness uniformity across the display panel.
Solution Approach 2:
The patent transitions from a conventional symmetric package structure to an asymmetric structure with elliptical or circular arc cross-section. This dimensional change in the package geometry creates different light distribution characteristics in different directions, allowing controlled angular distribution that covers gaps horizontally while limiting vertical light spread to prevent leakage.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The LED module ensures uniform brightness by enhancing light coverage in horizontal directions and minimizing light leakage by controlling light angles, thus addressing the issues of dark lines and light leakage in thinner LCDs.
Implementation Method 1
The package structure is almost like a semi-ellipsoid, which has an elliptic bottom surface and an ellipsoidal surface... The angular distribution of light field may be broader along the direction of the semi-major axis of the elliptic bottom surface, and the angular distribution of light field may be smaller along the direction of the semi-minor axis
Data Source
AI summary
A light emitting diode contains a package structure and a light emitting diode die embedded in the package structure. The package structure has an elliptic bottom surface having a semi-major axes and a semi-minor axis and a semi-ellipsoidal surface connecting and surrounding the edge of the elliptic bottom surface, wherein the maximum height of the ellipsoidal surface from the elliptic bottom surface is between the semi-major axes and the semi-minor axis.